Elevator-brake.



w. H. CHAPMAN.

ELEVATOR BRAKE.

APPLICATION HLED MAR. 10 19].).

I 1,207,861. Patented 11%. 12, 1916.

UNITED his PATENT OFFICE.

WILLIAM H. CHAPMAN, OF PORTLAND, MAINE.

ELEVATOR-BRAKE.

Application filed March 10, 1915.

To all 'UJ/l-O'Ift it may concern: I

Be it known that I, \VILLIAM. ll. Gnar- MAN, of Portland, in the county of Cumberland and State of Maine, have invented certain new and useful Improvements in Elevator-Brakes, of which the following is a specification.

My invention relates to elevators which are driven by polyphase alternating current motors and its object is to provide a brake mechanism which shall be silent and efficient in its operation, and a safeguard against runaway accidents in case of unsus pected interchange of two of the wires leading to the motor.

My invention is applied to brakes which are normally at the on position andis arranged to release the brake. This is usually done by means of a solenoid. 'It is well known that these solenoids operating on an alternating current are very noisy and ineliicient, requiring a very much larger consilmption of electrical energy than solenoids of corresponding power operated by direct current. It is also well known that electric motors driven by polyphase currents are reversed in their direction of rotation by the interchange of two of the wires leading to them. It sometimes happens that an interchange of two of the wires is made by careless workmen either at the power station supplying the current or outside on the pole lines, and inthis way disastrous results are liable to follow on any elevator driven from the system, because of the fact that the solenoids usually employed to releasethe brake will release it just the same whichever way the leads are connected, and will thus let the elevator run in the reverse direction with nothing to check its movements as the controlling devices are rendered inoperative by the interchange. My invention on the contrary provides a brake operating device that will not release'when two wires are thus in terchanged and the result will be to blow out a fuse and prevent accident to the elevator.

In carrying out my'invention I employ an auxiliary polyphase motor of the same phase as the main motor, the rotation of this auxiliary motor acting through'suitable mechanism to relieve the brake which is normally set. This auxiliary motor is made with a rotor free from teeth so thatit is noiseless when in operation.

My invention may Specification of Letters Patent.

. angle to each other, .a .pair;of sp ng best be understood by Q Patented Dec. 12, 1916.

s rial No. 13,466.

nected in the usual manner with the hoistmg drum,= (not shown), and 3, 4 and 5 the circuit wires to which the motor is connected. The brake levers 6 and 7 are forced into engagement with the hoisting drum 2 bymeans of a spring 8 in the usual manner, being normally engaged or on: The brake is released by means of a cam 10 which rotates between antifriction rolls Q t ese rolls being mounted on the adjacent ends of the brake lovers 6 and 7. The cam 10 is: 'ro- 'tated by means of a geared sector 11. 150

which it is attached and the geared sector in turn operated by the pinion 12 0f the auxiliary polyphase motor 13. I The wires 14, 15 and 16' connect the motor 13 with the circuit wires 3, 4 and 5 which 'supply the main motor. The two motors are of the same phase,'in this caseeach being a three phase motor. The geared sector is provi ed with stops whereby itsmotion in' opposite direction is-limited and as here shownf secur'e to a bracket 17 having two arms 20' 'fset at an 18 and 19. 'Each of, these stops i a bolt exten ing through an 'openin one of the arms secured in place by a pin and having a' spring 21 arranged to resist the blow from the segment. .This bracket with its stops issecured to the frame of the machnre and pro eats itlto an open. ace formed by cutting away a sector shape portion of the geared sector. The stops 18 and 19 come in contact with the edges of this space as the geared sector rotates first in one direction and then in another. The uppler edge of'the sector is provided with teet engage the teeth of the pinion and the lower which ortion of the sector is made solid so that it 1s in effect weighted in such a way as to tend always to return to its normal position in which position the cam is out of engagement with the rolls 9 and the brake is consequently set. "It is necessary in operating the elevator to providefor the reversal of orother good conducting the main motor without reversing the auxiliary motor. For this purpose I insert in the line between the main motor and the auxiliary motor a reversing switch operated in any well known manner from the elevator or otherwise.

One of the important features of my elevator is my manner of constructing the rotor of the auxiliary motor so that it will be noiseless.

Referring now to Figs. 2 and 3, 23 represents the'central shaft of the motor having on its end the pinion 12 already referred to. The rotor is made up of an iron core 24 in practice being a section of heavy wrought iron pipe. This core is secured to the shaft by plates 2,) formed of copper material and the I core is covered with a cylindrical sheath set; any desired deverage may beobtainedQ "to dissipate runs perfectly of. copper extending well beyond the ends of the core to give a large radiating surface the heat. This form of rotor silent because there are no teeth to vary the magnetic flux. The stator part of the motor is made-up in the usual manner being a ,'laminated iron ring 27 slotted to receive the coils. The parts are supported by a suitable frame 28 which it is not necessary to particularly describe. The relation between the lgeared sector and the pinion is such-that t e weight on the sector tends to when the current is motor, it drives the motor 1? switched off from the leased.

Theadvantages of my construction are,

motor to reverse and the brake to remain 1,2ov,se1

turn the rotor backward When the current is switched on ward and lifts the. ,weight at the same time the brake --is.re-

by varying the relative sizes ofthe 'pinion and the geared sector and any desired range of movement obtained as the motor Wlll continue to run until the brake is released.

The rotor is exceedingly simple and cheap-l? made and runs without noise. The an iary motor uses far less current than the solenoid in common use and the construction represents an important advance in the art in the direction of safety, efiiciency and freedom from objectionable sounds.

I claim:

1. In an elevator, the combination with a brake and brake drum of means for norwall holding the brake in engagement with the drum,"an electric motor, a pinion rotated by said motor, a geared sector engaging said pinion and weighted to cause its return to its normal position, a cam connected to said sectorand formed and positioned to force the brake out-of engagement with the drum when the sector is rotated in one direction.

2. In an elevator, the combination with a brake and brake drum of means for normally holding the brake in engagement with the drum, an electric motor, a pinion r0 tated by said motor, a geared sector engaged by said pinion, said sector being weighted to return it to.its normal position and having a recess formed therein'a pair sector for causing the disengagement of the brake and its-drum when the sector is rotated in one direction.

In' testimony whereof I have aflixed my signature, in presence of two witnesses.

WILLIAM H. CHAPMAN.

Witnesses: I

S. W. Barns, L. D. Roman. 

